Memory management problem
 

Hi everyone. I'm running Fedora 2 on a Compac Presario 2100. After a few initial problems getting Fedora 2 to install, my system has been running well for almost a year.

This morning I noticed my system was extremely slow when booting up. Upon logging in I noticed in the System Monitor application that none of the swap space is being used, that is it says Used Swap Space: 0 bytes of 510 MB. Additionally System Monitor reports that only about 175 MB of 441 MB of memory available are being used.

I am lucky that I can startup Firefox and post to this forum. More memory intensive applications will not run.

My "/" partition only has about 600 MB of free disk space. Could this be the problem?

I'm pretty sure this is not a hardware problem because my system is dual-boot and when I boot to Windoze I have no problems.

Linux gurus, please help.

If slowness is the problem, and your swap space is not being used, then I don't think it's a memory problem. Only if your RAM is full and your swap space is also filling up should you notice a big performance hit.

I'd look elsewhere for the cause of slowness. Try running 'top' in a terminal window to see what's eating the CPU and/or memory (you can press 'M' in 'top' to sort by memory usage).

I wish I knew of a comparable program for displaying disk usage by process, though. I've occasionally had large amounts of mysterious disk activity, and couldn't figure out what process was doing it. This may be part of your problem too--something using too much disk, preventing other programs from loading efficiently.

A process called udev seems to by using 90% of my CPU processing power. What is udev? What can I do to fix my problem?

I cleaned up my root partition and now I have more than 2 gigs free. Clearly disk space on the root partition was not the problem. I also booted to the memory test program that comes with the kernel. The RAM tests without errrors. The output of top is below.

Help?



top - 20:29:44 up 18 min, 4 users, load average: 4.60, 4.48, 3.06
Tasks: 102 total, 5 running, 97 sleeping, 0 stopped, 0 zombie
Cpu(s): 98.4% us, 1.0% sy, 0.3% ni, 0.0% id, 0.0% wa, 0.3% hi, 0.0% si
Mem: 451124k total, 447792k used, 3332k free, 28328k buffers
Swap: 522104k total, 0k used, 522104k free, 240304k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1268 root 15 -10 2740 436 1340 R 89.2 0.1 17:47.35 udev
2922 root 16 0 90916 19m 75m R 7.6 4.3 0:12.87 X
3206 jono 25 10 34364 20m 22m R 0.7 4.6 0:01.58 rhn-applet-gui
3262 jono 16 0 28004 14m 20m R 0.7 3.2 0:01.40 gnome-terminal
3333 jono 15 0 21436 9.9m 17m S 0.3 2.2 0:01.38 gnome-system-mo
1 root 15 0 2132 464 1316 S 0.0 0.1 0:05.02 init
2 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
3 root 5 -10 0 0 0 S 0.0 0.0 0:00.86 events/0
4 root 5 -10 0 0 0 S 0.0 0.0 0:00.00 kblockd/0
6 root 6 -10 0 0 0 S 0.0 0.0 0:00.00 khelper

If I kill off udev, the system is back to normal.

http://www.linuxquestions.org/questi...hreadid=263791

Is this safe to kill off udev? I found this thread, but when I go to System Services it does list udev as a startup process.

What version of kernel are you using? You can find out by typing 'uname -a' in a terminal window. udev handles your device filesystem (the /dev directory), so I don't think it's safe to kill unless you are using devfs (the 2.4.x kernel approach).

The udev howto might give you some clues. I don't know much about how udev works, or why it would be eating up so much CPU.

I'm running 2.6.5-1.358.

I couldn't find anything useful by following the link. If udev works with devices maybe there is something amuck with /etc/fstab ?

LABEL=/ / ext3 defaults 1 1
none /dev/pts devpts gid=5,mode=620 0 0
none /dev/shm tmpfs defaults 0 0
/dev/hda6 /home ext3 defaults 1 2
none /proc proc defaults 0 0
none /sys sysfs defaults 0 0
/dev/hda3 swap swap defaults 0 0
/dev/hda5 /mnt/vfat vfat users 0 0
/dev/sda1 /mnt/usb auto user,rw,noauto 0 0
/dev/cdrom /mnt/cdrom udf,iso9660 noauto,owner,kudzu,ro 0 0
/dev/cdwriter /mnt/cdwriter udf,iso9660 noauto,owner,kudzu,rw 0 0

I don't know for sure if you can simply uninstall udev. I think that you can. If you want to try that you can type this
rpm -e udev

You can try and re-install it. Maybe the program got corrupted somehow since it worked fine for so long. You need your FC2 cds. Search the CDs for the udev RPMs. Uninstall it with the command above. Then install it back with this:
rpm -Uhv /mnt/cdrom/path/to/udev-<fill-in-version>.rpm

Then there is the "dirty hack" way to do it. You can add this line to the file /etc/rc.d/rc.local:

killall udev

That line might need to be
killall udevd

It just depends on the name of the proccess that is running and taking up so much CPU. rc.local is executed after all the other services and daemons are started.

If it were me I'd research more to see if I could just completely uninstall it.

No wait... If it were me I'd just uninstall it and then get pissed because it won't boot back up and then have to fix that problem too! :)

I tried uninstalling and reinstalling udev with no success. My system still boots with udev as a runaway process after the reinstall.

I'm not really comfortable just killing the process in rc.local. I'm going to repost this as a new thread.

Thanks everyone.

I'd say the only reason not to kill it is if you need it. Do you ever plug any thing like usb or firewire into your system? If you don't you probably don't really need udev to run. I'd say kill it in rc.local and if your system starts acting odd in some other fashion then re-enable udev.

I do use a USB jump drive, but my hot plugging has never worked with it.

I have permanently uninstalled udev and my system seems to be functioning as usual. Unless anyone can give me a good reason why I need udev or my computer explodes, I'm going to leave it uninstalled.

Thanks everyone for your help.